Faceting Design Diagram: Precede – Tourmaline, Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

Precede Jeff Graham Facet Design

Precede Jeff Graham Facet Design

Precede (MIR83.JRG)

By Jeff R. Graham
Copyright 2005
91.2% Light Return
Angles for R.I. = 1.62
32 facets + 12 facets on girdle = 44
4-fold, mirror-image symmetry
96 index
L/W = 1.000 P/W = 0.450 C/W = 0.191
H/W = (P+C)/W+0.02 = 0.661 P/H = 0.681 C/H = 0.289
Vol./W^3 = 0.239

 

Addition # 10 – Cut in refractive indexes 1.62 to 2.14 with no changes. This is very interesting and not difficult to cut. It works well in light to medium saturations and is a good Garnet cut. Note: P3 just floats in, you can vary the facets. A table should be cut on larger stones.

Precede Jeff Graham Facet Design

Detailed faceting instructions by Jeff Graham available at The Rock Peddler

About the author
Jeff R. Graham
The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.
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